Darmstadt 2016 – scientific programme

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AKBP: Arbeitskreis Beschleunigerphysik

AKBP 8: Polarized Beams

AKBP 8.1: Talk

Tuesday, March 15, 2016, 16:30–16:45, S1/05 24

Development status of a test stand for semiconductor photocathodes with 60 keV spin-polarized beamline — •Neeraj Kurichiyanil, Joachim Enders, Martin Espig, Yuliya Fritzsche, Domenic Heichelt, Andreas Kaiser, Heidi Rösch, and Markus Wagner — Institut für Kernphysik, TU Darmstadt

A test facility for Photo-Cathode Activation, Test and Cleaning using atomic-Hydrogen (Photo-CATCH) is being constructed at TU Darmstadt’s Institute for Nuclear Physics (IKP) which houses the Superconducting Darmstadt Linear Accelerator (S-DALINAC). In order to improve the performance of the SDALINAC’s photoelectron source based on GaAs, systematic studies in terms of quantum efficiency (QE), cathode rejuvenation, lifetimes and polarization (P) have to be conducted on different photocathode types. These factors strongly depend on handling of the cathode, the vacuum condition in the chambers, cathode surface cleaning as well as preservation of stoichiometry, negative electron affinity (NEA) activation of the cathode and the type and structure of the semiconductor material. With Photo-CATCH, experiments such as atomic-hydrogen cleaning, multi-alkali and oxidant NEA activation of the cathode and tests of QE, P and lifetimes can be performed in an improved vacuum. Additionally, experiments with polarized-electron beams of up to 60 keV are foreseen.

Work supported in part by DFG through SFB 634 and by the state of Hesse through HIC for FAIR.